Conventional electrophotographic image-forming devices such as laser printers employ developer cartridges filled with toner. The developer cartridges are detachably mounted in the image-forming device.
This type of developer cartridge is partitioned into a filling chamber and a developing chamber. The filling chamber is filled with toner and includes an agitator that is driven to rotate therein. The developing chamber is provided with a supply roller and a developing roller disposed in contact with each other, and a thickness-regulating blade that applies pressure to the surface of the developing roller.
When the developer cartridge is mounted in the laser printer and the laser printer inputs power to the cartridge via a gear train, the agitator is driven to rotate and, by such rotations, conveys toner accommodated in the filling chamber into the developing chamber. The rotating supply roller in the developing chamber supplies this toner onto the developing roller, at which time the toner is tribocharged between the supply roller and the developing roller. As the developing roller continues to rotate, the toner supplied onto the surface of the developing roller passes between the thickness-regulating blade and the developing roller, at which time the toner is smoothed so that a thin layer of uniform thickness is carried on the developing roller.
This type of developer cartridge is mounted in the laser printer so that the developing roller opposes a photosensitive drum in the laser printer. As the thin layer of toner carried on the surface of the developing roller rotates opposite the photosensitive drum, the toner develops an electrostatic latent image formed on the surface of the photosensitive drum into a visible image. A transfer roller disposed in confrontation with the photosensitive drum causes the visible image to be transferred onto a sheet of paper as the sheet passes between the transfer roller and the photosensitive drum, thereby forming a desired image on the paper.
By mounting this type of developer cartridge in the laser printer and using the cartridge as described above, toner accommodated in the filling chamber is consumed. When the amount of toner remaining in the chamber becomes low, the user removes the used developer cartridge and inserts a new developer cartridge in its place.
Owing to the increasing trend toward environmental conservation in recent years, it is desirable that the used developer cartridges be recycled rather than discarded.
For example, U.S. Pat. publication No. 6,763,210 B2 proposes a method of reusing a used developer cartridge. In this method, the used developer cartridge is recovered and refilled with a toner having less fluidity than the suspension polymerized toner previously used in the developer cartridge, and greater fluidity than a crushed toner that has not undergone spherical processing, that is, an emulsion polymerized toner, or a suspension polymerized toner containing less additive than the suspension polymerized toner originally used in the developer cartridge.